IT1302129B1 - Polarization plant for automatic polarization of null-powered lens used in sunglasses - Google Patents

Abstract

Polarization plant has a coil polarizing film feeding station with collection of coils, concave lens feeding station, oriented convex lens feeding station to apply degrading coatings on the lens, vacuum film shaping station on spherical molds washing station (15) for pre-glued and finished lens film cutting and pelletization station for marking polarization axis of finished lens. The lens is moved to approach the glue bead with predetermined coupling speed such that a point contact is provided between the lens and the glue without air trapping. The lens axis does not coincide with bead axis and, after coupling, a diagonal motion of lens is accomplished until the lens is centered. A slight vertical pressure followed by circular rotary motion is applied to the lens for spreading the glue. Pre-glued lenses are washed by an automatic washing machine which has suitable detergents, ultrasound and rinsing techniques for washing. Either two washing machines or alternatively used single automatic washing machine is provided for washing the concave and convex lenses. The washing and gluing stations are enclosed in a depulverized room having filters for air flow. The finished lens are again subjected to washing by an automatic washing machine. A testing station is provided to test the cosmetic defect of finished lens. During the gluing phase, uniform pressure is applied to all portions of lens surfaces such that the uniformity of glue layer between the lens and the film is improved. The adhesive film used for polarization exhibits ultraviolet blocking phenomenon and has high resistance to impact breaking, aging, decolorization, delamination, etc. To enhance the catalyzation process, lamps having broad emission spectra are used along with special adhesives. An independent claim is also included for the manufacturing process of polarizing lenses. The concave and convex lenses from the corresponding feeding stations along with polarizing film from the coil polarizing film feeding station are sent to the vacuum film shaping station. The lenses are then glued and separated. The exceeding film on the finished lenses are eliminated by film cutting station. The polarization axis is marked on the surface of finished lenses by the pelletization station.